Communications networks are evolving rapidly, and network designers are constantly challenged to improve the efficiency, speed, and overall performance of their networks. In such an environment, asynchronous transfer mode (ATM) is emerging as the broadband data communications technology of choice. ATM networks support a variety of different service categories providing a variety of qualities of service (QoS). This variety of service options allows ATM to satisfy the needs of many different types of network clients.
In order to support the variety of service categories, ATM traffic management enforces policing and shaping schemes that control the traffic flow throughout the network. Traffic that violates the policing and shaping requirements of the network can either be rejected or it can be tuned or shaped so that it conforms. These capabilities help ATM to improve the overall performance of the network and to take full advantage of the available resources.
Traffic in an ATM network is typically carried along virtual channel connections (VCCs). A VCC on a particular link is uniquely identified by the combination of a virtual path identifier (VPI) and a virtual channel identifier (VCI). Traffic from a number of different sources may have a common destination, and as such, may be combined to produce a virtual path connection (VPC) that includes a number of individual VCCs. The VPC is uniquely identified by a VPI, which is contained within a field of the ATM cell header. Each VCC within the VPC is uniquely identified by a corresponding VCI value. When the VPC reaches its destination, the VCCs within the VPC can be segmented by using the unique VCI values corresponding to each VCC.
ATM connections are established using the physical resources available in a network. The physical resources of the network can be divided into virtual segments, referred to as trunk groups (TGs). Trunk groups can be partitioned to support a number of different service categories. New connections are admitted in ATM networks by a connection admission control (CAC) algorithm. In order to establish a new connection, the physical and virtual resources available for the connection must be accurately understood by the connection admission control (CAC) algorithm.
Modifications to the current structure of VPCs and their role in ATM networks may provide additional advantages in terms of maximizing network efficiency. However, if the CAC algorithms do not possess the full range of parameters describing these modified VPCs, optimal allocation of resources within the network will not occur.
Therefore, a need exists for a method and apparatus for supporting modified VPCs in an ATM network.